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USB Port Lithium-Ion/Polymer Battery Charger General Description
The AAT3688 BatteryManager™ is a highly integrated single cell lithium-ion/polymer battery charger IC designed to operate with USB port inputs. It requires the minimum number of external components. The AAT3688 precisely regulates battery charge voltage and current for 4.2V lithium-ion/polymer battery cells. Depending on the USB port type, the AAT3688 charge current can be programmed for two separate levels up to 500mA. An optional Charge Reduction Loop is built in to allow users to charge the battery with available current from a USB port, while keeping the port voltage regulated.
AAT3688
Features
• • •
BatteryManager™
Battery temperature and charge state are fully monitored for fault conditions. In the event of an over-voltage or over-temperature failure, the device will automatically shut down, thus protecting the charging device, control system, and the battery under charge. Status monitor output pins are provided to indicate the battery charge status by Applications directly driving two external LEDs. A serial interface www.DataSheet4U.com output is available to report any one of 14 various • Bluetooth™ Headsets status states to a microcontroller. • Cellular Telephones • Digital Still Cameras The AAT3688 is available in a Pb-free, thermally• Hand-Held PCs enhanced, space-saving 12-pin 3x3mm TDFN • MP3 Players package and is rated over the -40°C to +85°C tem• Personal Data Assistants (PDAs) perature range. • Other Lithium-Ion/Polymer Battery-Powered Devices
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USB Charger — Programmable up to 500mA Max 4.0V to 5.5V Input Voltage Range High Level of Integration With Internal: — Charging Device — Reverse Blocking Diode — Current Sensing Automatic Recharge Sequencing Charge Reduction Loop for USB Charging Battery Temperature Monitoring Full Battery Charge Auto Turn-Off Over-Voltage Protection Emergency Thermal Protection Power On Reset and Soft Start Serial Interface Status Reporting 12-Pin 3x3mm TDFN Package
Typical Application
Enable USB Input USB Hi/Lo Select
USB USBSEL USBH RSETH RSETL USBL BAT TS C2 10μF EN CHR
BATT+
AAT3688
GND
BATT-
DATA STAT1 STAT2
TEMP
Battery Pack
Serial Data
3688.2006.10.1.5
1
USB Port Lithium-Ion/Polymer Battery Charger Pin Descriptions
Pin #
1 2 3 4
AAT3688
Name
USB BAT GND CHR
Type
In In/Out Ground In/Out
Function
USB power supply input. Battery charging and sensing. Ground connection. Resistor divider to set USB voltage regulation for charge reduction mode. Leave this pin open for default 4.5V USB regulation point. Tie to USB pin to disable this function. Enable pin. Logic high enables the IC. Connect to 10kΩ NTC thermistor. Status report to microcontroller via serial interface, open-drain. Battery charge status indicator pin to drive an LED: active low, open-drain. Battery charge status indicator pin to drive an LED: active low, open-drain. When USB is present, use this pin to toggle between USBH and USBL charging.